Improve negative gravity handling on dropped items

src/main/java/com/minelittlepony/unicopia/client/render/WorldRenderDelegate.java

@@ -4,6 +4,8 @@ import javax.annotation.Nullable;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.entity.Equine;
+import com.minelittlepony.unicopia.entity.ItemImpl;
 import com.minelittlepony.unicopia.entity.Living;
 import com.minelittlepony.unicopia.entity.behaviour.Disguise;
 import com.minelittlepony.unicopia.entity.player.Pony;
@@ -32,7 +34,28 @@ import net.minecraft.util.math.Vec3d;
 public class WorldRenderDelegate {
     public static final WorldRenderDelegate INSTANCE = new WorldRenderDelegate();
 
-    public boolean onEntityRender(EntityRenderDispatcher dispatcher, Living<?> pony,
+    public boolean onEntityRender(EntityRenderDispatcher dispatcher, Equine<?> pony,
+            double x, double y, double z, float yaw,
+            float tickDelta, MatrixStack matrices, VertexConsumerProvider vertices, int light) {
+
+        if (pony instanceof ItemImpl) {
+            matrices.push();
+
+            if (pony.getPhysics().isGravityNegative()) {
+                matrices.translate(0, -((ItemImpl) pony).getMaster().getHeight() * 1.1, 0);
+            }
+
+            return false;
+        }
+
+        if (pony instanceof Living) {
+            return onLivingRender(dispatcher, (Living<?>)pony, x, y, z, yaw, tickDelta, matrices, vertices, light);
+        }
+
+        return false;
+    }
+
+    private boolean onLivingRender(EntityRenderDispatcher dispatcher, Living<?> pony,
             double x, double y, double z, float yaw,
             float tickDelta, MatrixStack matrices, VertexConsumerProvider vertexConsumers, int light) {
 
@@ -84,12 +107,14 @@ public class WorldRenderDelegate {
         return false;
     }
 
-    public void afterEntityRender(Living<?> pony, MatrixStack matrices) {
+    public void afterEntityRender(Equine<?> pony, MatrixStack matrices) {
 
-        matrices.pop();
+        if (pony instanceof ItemImpl || pony instanceof Living) {
+            matrices.pop();
 
-        if (pony.getPhysics().isGravityNegative()) {
+            if (pony instanceof Living && pony.getPhysics().isGravityNegative()) {
-            flipAngles(pony.getMaster());
+                flipAngles(((Living<?>)pony).getMaster());
+            }
         }
     }
 

src/main/java/com/minelittlepony/unicopia/entity/Creature.java

@@ -25,12 +25,13 @@ import net.minecraft.nbt.CompoundTag;
 public class Creature extends Living<LivingEntity> {
 
     private static final TrackedData<CompoundTag> EFFECT = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.TAG_COMPOUND);
+    public static final TrackedData<Float> GRAVITY = DataTracker.registerData(LivingEntity.class, TrackedDataHandlerRegistry.FLOAT);
 
     private static final LevelStore LEVELS = Levelled.fixed(0);
 
     public static void boostrap() {}
 
-    private final Physics physics = new EntityPhysics<>(this);
+    private final Physics physics = new EntityPhysics<>(this, GRAVITY);
 
     public Creature(LivingEntity entity) {
         super(entity, EFFECT);

src/main/java/com/minelittlepony/unicopia/entity/EntityPhysics.java

@@ -10,6 +10,7 @@ import net.minecraft.block.BlockState;
 import net.minecraft.block.FenceGateBlock;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.LivingEntity;
+import net.minecraft.entity.data.TrackedData;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.particle.BlockStateParticleEffect;
 import net.minecraft.particle.ParticleTypes;
@@ -20,12 +21,21 @@ import net.minecraft.util.math.Vec3d;
 
 public class EntityPhysics<T extends Owned<? extends Entity>> implements Physics, Copieable<EntityPhysics<T>> {
 
-    private float gravity = 1;
+    private final TrackedData<Float> gravity;
 
     protected final T pony;
 
-    public EntityPhysics(T pony) {
+    public EntityPhysics(T pony, TrackedData<Float> gravity) {
+        this(pony, gravity, true);
+    }
+
+    public EntityPhysics(T pony, TrackedData<Float> gravity, boolean register) {
         this.pony = pony;
+        this.gravity = gravity;
+
+        if (register) {
+            this.pony.getMaster().getDataTracker().startTracking(gravity, 1F);
+        }
     }
 
     @Override
@@ -86,7 +96,12 @@ public class EntityPhysics<T extends Owned<? extends Entity>> implements Physics
 
     @Override
     public void setBaseGravityModifier(float constant) {
-        gravity = constant;
+        pony.getMaster().getDataTracker().set(gravity, constant);
+    }
+
+    @Override
+    public float getBaseGravityModifier() {
+        return pony.getMaster().getDataTracker().get(gravity);
     }
 
     @Override
@@ -97,26 +112,26 @@ public class EntityPhysics<T extends Owned<? extends Entity>> implements Physics
             if (((LivingEntity)master).getAttributes() == null) {
                 // may be null due to order of execution in the constructor.
                 // Will have the default (1) here in any case, so it's safe to ignore the attribute at this point.
-                return gravity;
+                return getBaseGravityModifier();
             }
-            return gravity * (float)((LivingEntity)master).getAttributeValue(PlayerAttributes.ENTITY_GRAVTY_MODIFIER);
+            return getBaseGravityModifier() * (float)((LivingEntity)master).getAttributeValue(PlayerAttributes.ENTITY_GRAVTY_MODIFIER);
         }
 
-        return gravity;
+        return getBaseGravityModifier();
     }
 
     @Override
     public void copyFrom(EntityPhysics<T> other) {
-        gravity = other.gravity;
+        setBaseGravityModifier(other.getBaseGravityModifier());
     }
 
     @Override
     public void toNBT(CompoundTag compound) {
-        compound.putFloat("gravity", gravity);
+        compound.putFloat("gravity", getBaseGravityModifier());
     }
 
     @Override
     public void fromNBT(CompoundTag compound) {
-        gravity = compound.getFloat("gravity");
+        setBaseGravityModifier(compound.getFloat("gravity"));
     }
 }

src/main/java/com/minelittlepony/unicopia/entity/ItemImpl.java

@@ -21,26 +21,25 @@ import net.minecraft.nbt.CompoundTag;
 import net.minecraft.particle.ParticleEffect;
 import net.minecraft.particle.ParticleTypes;
 import net.minecraft.util.ActionResult;
-import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.Tickable;
 import net.minecraft.util.math.Vec3d;
 
 public class ItemImpl implements Equine<ItemEntity>, Owned<ItemEntity> {
     private static final TrackedData<Integer> ITEM_RACE = DataTracker.registerData(ItemEntity.class, TrackedDataHandlerRegistry.INTEGER);
+    private static final TrackedData<Float> ITEM_GRAVITY = DataTracker.registerData(ItemEntity.class, TrackedDataHandlerRegistry.FLOAT);
 
     private final ItemEntity owner;
-    private Race serverRace;
 
-    private final Physics physics = new EntityPhysics<>(this);
+    private final ItemPhysics physics = new ItemPhysics();
+
+    private Race serverRace;
 
     public ItemImpl(ItemEntity owner) {
         this.owner = owner;
+        owner.getDataTracker().startTracking(ITEM_GRAVITY, 1F);
         owner.getDataTracker().startTracking(ITEM_RACE, Race.HUMAN.ordinal());
     }
 
-    @Override
-    public void tick() {
-    }
-
     @Override
     public boolean beforeUpdate() {
 
@@ -92,24 +91,15 @@ public class ItemImpl implements Equine<ItemEntity>, Owned<ItemEntity> {
             }
         }
 
-        if (physics.isGravityNegative()) {
-            owner.setNoGravity(true);
-            owner.setOnGround(owner.verticalCollision);
-
-            float g = 0.98f;
-            if (owner.isOnGround()) {
-               g *= owner.world.getBlockState(owner.getBlockPos().up()).getBlock().getSlipperiness();
-            }
-
-            owner.setVelocity(owner.getVelocity()
-                    .add(0, physics.calcGravity(-0.04D), 0)
-                    .multiply(g, 1, g));
-
-        }
 
         return false;
     }
 
+    @Override
+    public void tick() {
+        physics.tick();
+    }
+
     @Override
     public Physics getPhysics() {
         return physics;
@@ -151,6 +141,49 @@ public class ItemImpl implements Equine<ItemEntity>, Owned<ItemEntity> {
         ActionResult onGroundTick(IItemEntity entity);
     }
 
+    class ItemPhysics extends EntityPhysics<ItemImpl> implements Tickable {
+
+        private float serverGravity;
+
+        public ItemPhysics() {
+            super(ItemImpl.this, ITEM_GRAVITY, false);
+        }
+
+        @Override
+        public void tick() {
+            if (!owner.world.isClient) {
+                float gravity = getBaseGravityModifier();
+                if (gravity != serverGravity) {
+                    serverGravity = gravity;
+                    setBaseGravityModifier(gravity == 0 ? 1 : gravity * 2);
+                    setBaseGravityModifier(gravity);
+                }
+            }
+
+            if (isGravityNegative() && !owner.getStack().isEmpty()) {
+                owner.setNoGravity(true);
+                owner.addVelocity(
+                        0,
+                        0.04
+                        + calcGravity(-0.04D), // apply our own
+                    0
+                );
+
+                if (!owner.isOnGround()
+                        || Entity.squaredHorizontalLength(owner.getVelocity()) > 9.999999747378752E-6D) {
+
+                    float above = 0.98f;
+                    if (owner.verticalCollision) {
+                       above *= owner.world.getBlockState(owner.getBlockPos().up()).getBlock().getSlipperiness();
+                       //above /= 9;
+                    }
+
+                    owner.setVelocity(owner.getVelocity().multiply(above, 1, above));
+                }
+            }
+        }
+    }
+
     public interface ClingyItem {
         ClingyItem DEFAULT = stack -> {
             return EnchantmentHelper.getLevel(UEnchantments.CLINGY, stack) > 0;

src/main/java/com/minelittlepony/unicopia/entity/Physics.java

@@ -13,6 +13,8 @@ public interface Physics extends NbtSerialisable {
 
     float getGravityModifier();
 
+    float getBaseGravityModifier();
+
     void setBaseGravityModifier(float constant);
 
     boolean isFlying();

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerAttributes.java

@@ -1,5 +1,7 @@
 package com.minelittlepony.unicopia.entity.player;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.UUID;
 
 import com.minelittlepony.unicopia.Race;
@@ -16,6 +18,8 @@ import net.minecraft.util.registry.Registry;
 
 public class PlayerAttributes implements Tickable {
 
+    public static final List<EntityAttribute> REGISTRY = new ArrayList<>();
+
     public static final EntityAttribute EXTENDED_REACH_DISTANCE = register("unicopia.pegasus.reach", new ClampedEntityAttribute("player.reachDistance", 0, 0, 10).setTracked(true));
     public static final EntityAttribute EXTRA_MINING_SPEED = register("unicopia.earth.mining_speed", new ClampedEntityAttribute("player.miningSpeed", 1, 0, 5).setTracked(true));
     public static final EntityAttribute ENTITY_GRAVTY_MODIFIER = register("unicopia.player.gravity", (new EntityAttribute("player.gravityModifier", 1) {}).setTracked(true));
@@ -66,6 +70,7 @@ public class PlayerAttributes implements Tickable {
     }
 
     private static EntityAttribute register(String id, EntityAttribute attribute) {
+        REGISTRY.add(attribute);
         return Registry.register(Registry.ATTRIBUTE, id, attribute);
     }
 }

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerPhysics.java

@@ -4,6 +4,7 @@ import com.minelittlepony.unicopia.FlightType;
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.USounds;
 import com.minelittlepony.unicopia.ability.magic.Spell;
+import com.minelittlepony.unicopia.entity.Creature;
 import com.minelittlepony.unicopia.entity.EntityPhysics;
 import com.minelittlepony.unicopia.entity.Jumper;
 import com.minelittlepony.unicopia.entity.player.MagicReserves.Bar;
@@ -47,7 +48,7 @@ public class PlayerPhysics extends EntityPhysics<Pony> implements Tickable, Moti
     private final PlayerDimensions dimensions;
 
     public PlayerPhysics(Pony pony) {
-        super(pony);
+        super(pony, Creature.GRAVITY);
         dimensions = new PlayerDimensions(pony, this);
     }
 

src/main/java/com/minelittlepony/unicopia/mixin/client/MixinEntityRenderDispatcher.java

@@ -12,7 +12,6 @@ import net.minecraft.client.render.VertexConsumerProvider;
 import net.minecraft.client.render.entity.EntityRenderDispatcher;
 import net.minecraft.client.util.math.MatrixStack;
 import net.minecraft.entity.Entity;
-import net.minecraft.entity.LivingEntity;
 
 @Mixin(EntityRenderDispatcher.class)
 abstract class MixinEntityRenderDispatcher {
@@ -21,9 +20,6 @@ abstract class MixinEntityRenderDispatcher {
 
     @Inject(method = RENDER, at = @At("HEAD"), cancellable = true)
     private <E extends Entity> void beforeRender(E entity, double x, double y, double z, float yaw, float tickDelta, MatrixStack matrices, VertexConsumerProvider vertexConsumers, int light, CallbackInfo info) {
-        if (!(entity instanceof LivingEntity)) {
-            return;
-        }
         if (WorldRenderDelegate.INSTANCE.onEntityRender((EntityRenderDispatcher)(Object)this, Equine.of(entity), x, y, z, yaw, tickDelta, matrices, vertexConsumers, light)) {
             info.cancel();
         }
@@ -31,9 +27,6 @@ abstract class MixinEntityRenderDispatcher {
 
     @Inject(method = RENDER, at = @At("RETURN"))
     private <E extends Entity> void afterRender(E entity, double x, double y, double z, float yaw, float tickDelta, MatrixStack matrices, VertexConsumerProvider vertexConsumers, int light, CallbackInfo info) {
-        if (!(entity instanceof LivingEntity)) {
-            return;
-        }
         WorldRenderDelegate.INSTANCE.afterEntityRender(Equine.of(entity), matrices);
     }
 }

src/main/java/com/minelittlepony/unicopia/projectile/MagicProjectileEntity.java

@@ -46,13 +46,14 @@ import net.minecraft.world.World;
 public class MagicProjectileEntity extends ThrownItemEntity implements Magical, Caster<LivingEntity> {
 
     private static final TrackedData<Float> DAMAGE = DataTracker.registerData(MagicProjectileEntity.class, TrackedDataHandlerRegistry.FLOAT);
+    private static final TrackedData<Float> GRAVITY = DataTracker.registerData(MagicProjectileEntity.class, TrackedDataHandlerRegistry.FLOAT);
     private static final TrackedData<Boolean> HYDROPHOBIC = DataTracker.registerData(MagicProjectileEntity.class, TrackedDataHandlerRegistry.BOOLEAN);
     private static final TrackedData<CompoundTag> EFFECT = DataTracker.registerData(MagicProjectileEntity.class, TrackedDataHandlerRegistry.TAG_COMPOUND);
     private static final LevelStore LEVELS = Levelled.fixed(1);
 
     private final EffectSync effectDelegate = new EffectSync(this, EFFECT);
 
-    private final EntityPhysics<MagicProjectileEntity> physics = new EntityPhysics<>(this);
+    private final EntityPhysics<MagicProjectileEntity> physics = new EntityPhysics<>(this, GRAVITY, false);
 
     private BlockPos lastBlockPos;
 
@@ -67,7 +68,8 @@ public class MagicProjectileEntity extends ThrownItemEntity implements Magical,
     @Override
     protected void initDataTracker() {
         super.initDataTracker();
-        getDataTracker().startTracking(DAMAGE, (float)0);
+        getDataTracker().startTracking(GRAVITY, 1F);
+        getDataTracker().startTracking(DAMAGE, 0F);
         getDataTracker().startTracking(EFFECT, new CompoundTag());
         getDataTracker().startTracking(HYDROPHOBIC, false);
     }